1. Field of the Invention
The present invention relates to a projection display apparatus that forms an optical image corresponding to image information by optically processing a light beam emitted from a light source lamp and projects this optical image with a projection lens unit on a projection screen under magnification.
2. Description of Related Art
Until now, a projection display apparatus is well known, the projection display apparatus which comprises an optical unit that forms an optical image corresponding to image information by optically processing a light beam emitted from a light source lamp and projects this optical image with a projection lens unit on a projection screen under magnification, a power supply unit supplying power to this optical unit and the light source lamp, an outer case containing the optical unit and the power supply unit, and a plurality of circuit boards for controlling the optical unit.
According to this type of projection display apparatus, it is possible to project an image in a computer and the like on a projection screen under magnification. Therefore, it is possible to effectively perform multimedia presentation using a computer and the like.
A metal halide lamp, a xenon lamp, a high-pressure mercury-vapor lamp, and the like are used as the light source lamps in projection display apparatuses. Although these light source lamps can emit comparatively stable light for some thousands hours from operation start, lifetime of the lamps expires when the lamps are used for more than the hours, brightness of the lamps remarkably drops, and the light source lamps may burst.
Therefore, in a conventional projection display apparatus, a lifetime value of operation time of a light source lamp is set according to a kind of the light source lamp. Furthermore, a mechanism, extinguishing the light source lamp when the accumulated operation time of the light source lamp built in the projection display apparatus reaches this lifetime value, is provided. Owing to this, the above-described problems of burst of the light source lamp and the like are treated.
Nevertheless, there are following problems in this type of conventional projection display apparatus.
{circle around (1)} Thus, the lifetime of a light source lamp is not determined by only its accumulated operation time, but, for example, a lighting count of the light source lamp also affects the lifetime of the light source lamp since the light source lamp is loaded at the time of turning on. Therefore, there arises a problem that the light source lamp reaches its lifetime before the light source lamp reaches a lifetime value set in regard to its operation time.
{circle around (2)} In addition, since the light source lamp is gradually weary with its operation time increasing, the brightness of the light source lamp is apt to gradually decrease before the light source lamp reaches its lifetime value. Therefore, it is not preferable to suddenly extinguish the light source lamp at the time of the accumulated operation time reaching its lifetime value. Alternatively, it is preferable that a user knows information such as the accumulated operation time of the light source lamp beforehand and replaces the light source lamp according to states.
An object of the present invention is to provide a projection display apparatus that forms an optical image corresponding to image information by optically processing a light beam emitted from a light source lamp and projects this optical image with a projection lens unit on a projection screen under magnification, and that can always turn on the light source lamp in a proper state.
In order to achieve the object, a projection display apparatus according to the present invention is a projection display apparatus that forms an optical image corresponding to image information by optically processing a light beam emitted from a light source lamp and projects this optical image with a projection lens unit on a projection screen under magnification. This projection display apparatus may include a lighting count detector that detects a lighting count of the light source lamp, replacement warning unit that outputs a warning signal, which urges a user to replace the light source lamp, in case where the lighting count detected by this lighting count detection reaches a predetermined value, and a display unit that displays the lighting count and/or the warning signal.
Here, the predetermined value at which the replacement warning unit outputs the warning signal can be set according to a lifetime value set for the light source lamp. For example, if the lifetime value of the lighting count of the light source lamp is set at 2000 times, the predetermined value can be set at 1900 times.
In addition, as the display unit, various types of devices such as a projected image from a projection display apparatus, an indicator such as an LED that is provided in a projection display apparatus, a display of a computer connected to a projection display apparatus, and the like can be used.
According to the present invention like this, since the projection display apparatus comprises the lighting count detection means, it is possible to further accurately grasp the actual lifetime of the light source lamp built in the projection display apparatus by detecting the lighting count affecting the lifetime of the light source lamp. Hence, it is possible to use the light source lamp in an always proper state. Furthermore, since the projection display apparatus comprises the replacement warning unit, it is possible to replace the light source lamp before the forcible extinguishing unit operates because of the operation time of the light source lamp reaching its lifetime value. Moreover, similarly, it is possible to use the light source lamp in the always proper state without the brightness of the light source lamp extremely dropping in use.
In the above configuration, it is preferable that the above-described projection display apparatus comprises lighting inhibition means that inhibits the lighting of the light source lamp in case where the lighting count reaches a lifetime value set for the light source lamp, and a lifetime warning unit that outputs on the display unit a warning signal of giving a warning that the light source lamp reaches its lifetime value.
Here, as the display unit means on which the lifetime warning unit outputs the warning signal, an indicator such as an LED provided in the projection display apparatus or a display of a computer connected to the projection display apparatus is preferable. This is because a projected image of the projection display apparatus is not displayed by the lighting inhibitor.
Thus, since the projection display apparatus comprises the lighting inhibitor lighting of the light source lamp is inhibited by the lighting inhibitor even if the light source lamp reaches its lifetime thereafter when the light source lamp was not replaced at the time of the replacement warning signal was displayed. Therefore, it is possible to prevent the light source lamp from bursting and so forth.
In addition, it is preferable that the above-described projection display apparatus comprises an operation time detector time that detects the operation time of the light source lamp, and that the replacement warning unit is constructed so that the replacement warning unit issues the above-described warning signal in case where any one of the lighting count and operation time reaches a predetermined value.
Thus, since the replacement warning unit is constructed in this manner, it is possible to judge the replacement timing of the light source lamp from the state of the lighting count and operation time, and to use the light source lamp in the further proper state.
Furthermore, it is preferable that the above-described projection display apparatus comprises a forcible extinguishing unit that forcibly extinguishes the light source lamp in case where the operation time detected by the operation time detector reaches the lifetime value set for the light source lamp.
Thus, since the projection display apparatus comprises the forcible extinguishing unit it is possible to prevent the light source lamp from bursting and so forth since the light source lamp is forcibly extinguished by the forcible extinguishing unit in case where the operation time of the light source lamp reaches the lifetime value in lighting.
Further, it is preferable that the above-described display unit is an image display unit for constructing the projection display apparatus.
Thus, since the display unit that displays the warning signal is the image display unit it is possible to grasp the information of the light source lamp such as the lighting count and operation time as actual values on a screen. Furthermore, since it is possible to use the projection display apparatus with a user confirming the state of the light source lamp, it is possible to use the light source lamp in the further proper state.
In addition, it is preferable that the above-described lighting count detector comprises a lighting count recorder recording the lighting count and this lighting count recorder is composed of nonvolatile memory that does not lose the recorded information even if the power of the projection display apparatus is shut off.
Here, as the nonvolatile memory, it is preferable that memory in which the recorded information can be written and cleared is adopted, and, for example, E2PROM (Erasable Programmable Read Only memory), or E2PROM (Electrically Erasable Programmable Read Only memory) can be adopted. In addition, it is preferable that a partial area of this nonvolatile memory is used as an operation time recorder recording the operation time.
Thus, since the lighting count recorder is composed of the nonvolatile memory, it is possible to hold the record of the lighting count of the light source lamp even if the power of the projection display apparatus is shut off.